Abstract:
Floods are common phenomena within the Ankobra estuary. However,
the unavailability of records on the nature of floods, exposure of communities
to floods and a flood risk map tend to limit effective flood risk control and
management within the estuary. This study therefore sought to assess flood
risk within the Ankobra estuary and examine how geodesign can be used as a
flood risk reduction strategy within the plan.
The research techniques employed in the study include interviews,
community mapping, observation, measurements (tape) and geographic
information systems techniques (onscreen digitising, global positioning system
mapping, spatial multi-criteria evaluation and geodesign). Results from the
study indicate that the estuary experiences three types of flood (riverine,
coastal and urban). Risk levels derived ranged from extreme, 0.75 – 1; high,
0.5 – 0.74; medium 0.25 – 0.49 to low, 0 – 0.24. The extreme risk zone
covered an area of 46,725m2; high risk zone covered 701,525m2; moderate
risk zone, 248,150m2 and low risk zone, 9,167,758m2.
Geodesign simulations (change of height foundation of buildings and
remodelled landscape including drainage system) were undertaken. They
produced more desirable result than the original risk levels. It was
recommended that persons within high risk zones after the geodesign
simulations should be relocated to low risk zones.
